Blood tests of people reporting long-term Covid conditions show that people who have the condition have clear biological differences from those who do not.

The report provides the first piece of evidence showing that people who suffer from the difficult-to-define condition show noticeable differences in their biology compared to people who don’t.

The results of the first-of-its-kind study mark major advances in diagnosing and treating the enigmatic condition that affects an estimated nine million Americans.

Long Covid consists of a constellation of symptoms that persist after a person has recovered, including persistent fatigue and brain fog. Patients are often dismissed by doctors who think it is all in their heads or that it is another condition entirely.

Researchers from Yale University and Mount Sinai Hospital relied on artificial intelligence to analyze hundreds of blood samples from people with and without long-term Covid. The biological differences they identified suggest that symptoms can be treated with experimental drugs.

Long Covid is estimated to affect between nine and twenty million Americans. It is difficult to diagnose as most clinical diagnostic tests, such as urinalysis and X-rays, are normal. But the latest findings suggest that blood tests may be useful in identifying possible treatments for symptoms

Identifying specific biomarkers of long Covid is a big win for patients repeatedly dismissed by doctors who think the symptoms are all in their heads

Identifying specific biomarkers of long Covid is a big win for patients repeatedly dismissed by doctors who think the symptoms are all in their heads

Their findings could pave the way for simple blood tests to diagnose lung Covid, which has historically been difficult because clinical tests and X-rays typically yield normal results.

The study, led by Dr David Putrino, a physiotherapist and rehabilitation expert at Mount Sinai, involved an analysis of more than 270 blood samples from people who had fully recovered from a confirmed case of Covid, people with active long-term Covid symptoms for at most at least four months after a confirmed COVID-19 infection, and those without previous Covid infection.

Dr. Putrino said: ‘These findings are important – they may lead to more sensitive testing for long COVID patients and personalized treatments for long COVID patients that have until now lacked proven scientific support.’

The analysis included samples taken between January 2021 and June 2022. It was based on both blood tests and a thorough questionnaire for participants to detail their symptoms, quality of life and medical history.

Some of the biomarkers the authors of the groundbreaking study identified include abnormal activity of a certain type of immune cell called T cells.

The poor functioning of these cells can lead to chronic inflammation which is thought to be the cause of a range of long-lasting Covid symptoms, ranging from fatigue and joint pain to cognitive problems.

Researchers also found that compared to non-long Covid patients, people with symptoms had around half the amount of cortisol, the body’s main stress hormone.

A deficiency of this hormone leads, among other things, to fatigue problems when falling asleep and waking up in the morning.

Finally, the team found that the common Epsteine-Barr virus lay dormant in long-term Covid-19 sufferers and then reactivated.

This virus causes mononucleosis, commonly known as mono, and is thought to contribute to many long-term Covid symptoms.

Dr. Akiko Iwasaki, a biologist at the Yale School of Medicine and co-author of the study, said: ‘We are pleased to see such clear differences in the immune phenotypes in people with and without long COVID.

‘These markers need to be validated in larger studies but provide a first step in dissecting the disease pathogenesis of long COVID.’

The machine learning algorithm they used was able to distinguish those with long Covid-19 from those without Covid-19, with 96 percent accuracy.

Dr. Putrino added: ‘This work is so exciting because it is among the first to show us clear, measurable differences in the blood biomarkers of people with long-term COVID-19, compared to people who have fully recovered from an acute infection and a group people who have never done that before. are infected with SARS-CoV-2.

‘These findings show us that people with long COVID are living with a disease process that is detectable using the blood test protocols outlined in the study, but also varies from patient to patient depending on their specific medical history.’